848
FXPQ50 PGUM 231932
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
532 AM CHST THU APR 24 2025
MARIANAS UPDATE
THERE WAS LITTLE CHANGE TO THE FORECAST. RADAR REVEALS MINIMAL
SHOWERS NEAR AND UPSTREAM OF THE MARIANAS EARLY THIS MORNING, AS
YESTERDAY'S TROUGH SHIFTS NORTHWESTWARD AWAY FROM COASTAL WATERS.
PWATS AVERAGE 1.6 INCHES ACROSS THE AREA, WITH LOWER VALUES JUST
UPSTREAM TO THE EAST-SOUTHEAST. EXPECT MOSTLY SUNNY SKIES AND CLEAR
SKIES TODAY, WITH A SLIGHT, GRADUAL INCREASE IN MOISTURE AND SHOWER
CHANCES THROUGH THE WEEKEND. ONLY ISOLATED SHOWERS ARE EXPECTED
THROUGH THE FORECAST PERIOD AS THIS DRY TRADE PATTERN PERSISTS.
LOCAL BUOY DATA INDICATES COMBINED SEAS OF AROUND 3 TO 4 FEET, WHICH
WILL INCREASE BY A FOOT OR TWO OVER THE NEXT FEW DAYS AS TRADE SWELL
AND INCOMING NORTH SWELL INCREASE. BENIGN SEA CONDITIONS ARE EXPECTED
THROUGH THE FORECAST PERIOD.
FIRE WEATHER
0.05 INCHES OF RAIN FELL AT THE GUAM INTERNATIONAL AIRPORT YESTERDAY.
THIS ALLOWED THE KBDI TO INCREASE SLIGHTLY WITH TODAY'S READING AT
670, WHICH REMAINS IN THE HIGH CATEGORY. GENTLE TO MODERATE TRADE
WINDS ARE EXPECTED OVER THE NEXT FEW DAYS AS A COL PASSES NORTH OF
THE ISLANDS, WHICH WILL PREVENT CRITICAL RED FLAG CONDITIONS FROM
BEING REACHED. HOWEVER, FIRE DANGER WILL REMAIN ELEVATED, ESPECIALLY
AT HIGHER TERRAIN WHERE STRONGER WINDS ARE EXPECTED. AFTERNOON
RELATIVE HUMIDITY VALUES WILL CONTINUE TO FALL NEAR 60 PERCENT. A
WETTING RAIN IS NOT EXPECTED FOR THE NEXT FEW DAYS AND THE KBDI WILL
LIKELY CONTINUE TO GRADUALLY CLIMB THROUGH THE WEEKEND.
EASTERN MICRONESIA UPDATE
NO SIGNIFICANT CHANGES WERE MADE TO THE FORECAST, WITH THE MAIN FOCUS
PUT TO REFINING TEMPERATURES AND POPS (PROBABILITY OF PRECIPITATION),
ESPECIALLY AT KOSRAE. HERE, AN AREA OF CONVERGENCE DELINEATES THE
LEAD EDGE OF A SUBTLE TROUGH. THOUGHT ABOUT INCREASING SHOWER
COVERAGE TO NUMEROUS (60 OR 70 PERCENT PROBABILITIES), BUT, CURRENTLY
OBSERVATIONS AND MODEL FORECASTS IN THE SHORT TERM KEEP THINGS AS
HIGH-END SCATTERED COVERAGE (50 PERCENT PROBABILITIES).
GENTLE TO MODERATE WINDS WILL PREVAIL WITH SEAS IN THE 4 TO 6 FOOT
RANGE, TYPICAL FOR THIS TIME OF YEAR.
WESTERN MICRONESIA UPDATE
NO SIGNIFICANT CHANGES WERE MADE, WITH THE GREATEST FOCUS PLACED
OVER THE SOUTHERN THIRD OF PALAU FOR POPS AND QPF (QUANTITATIVE
PRECIPITATION FORECAST - HOW MUCH RAIN YOU'LL GET).
PALAU (MAINLY SOUTHERN PORTIONS):
THE MODELS REMAIN CONSISTENT WITH THE NEAR-EQUATORIAL TROUGH FORECAST
(NET), GRADUALLY DEVELOPING A MODEST WWB (WESTERLY WIND BURST) IN THE
NEXT 24 TO 36 HOURS, CAUSING THE NET TO SLOWLY SLOSH NORTHWARD SOME.
SOUTHERN AREAS OF PALAU, ESPECIALLY NEAR HELEN'S REEF, AND MARITIME
TRAFFIC CAN EXPECT TO SEE SHOWER COVERAGE AND INTENSITY TO INCREASE
SOME BY THEN, WHILE SPREADING SCATTERED SHOWERS NORTHWARD AS THE
TROUGH MOVES.
YAP AND CHUUK:
CHUUK WILL ALSO SEE AN UPTICK IN SHOWER COVERAGE, AS A SURFACE TROUGH
CURRENTLY TO YOUR EAST AND SOUTHEAST MOVES OVERHEAD TONIGHT INTO
TOMORROW. FOR YAP, LOOK FOR ISOLATED SHOWERS TO CONTINUE THROUGH
TOMORROW.
PREV DISCUSSION
/ISSUED 512 PM CHST WED APR 23 2025/
MARIANAS SYNOPSIS...
GENTLE TO MODERATE TRADES PREVAIL IN THE REGION. SATELLITE IMAGERY
AND DOPPLER RADAR INDICATE MOSTLY CLEAR SKIES OVER THE COASTAL WATERS,
WITH SOME SHOWERS OVER SAIPAN. THE BUOYS INDICATE SEAS ARE 3 TO 4
FEET.
DISCUSSION...
LITTLE CHANGE HAS BEEN MADE TO THE FORECAST. CONDITIONS ARE EXPECTED
TO REMAIN MOSTLY DRY ACROSS THE REGION, WITH STRONG INDICATORS FOR
CLEAR STARRY SKIES THURSDAY NIGHT, AS PWATS UPSTREAM CONTINUE TO SIT
AT OR BELOW 1.5 INCHES. THIS TREND IS ALSO SUPPORTED BY A SUBTROPICAL
HIGH DEVELOPING AT THE LEADING EDGE OF OKINAWA'S SOUTHEASTERN COASTAL
WATERS, ALLOWING A COL TO FORM TO THE NORTH OF THE MARIANAS, FURTHER
STABILIZING THE LOCAL ATMOSPHERE FOR EXTENDED PERIODS OF SHOWER-FREE
DAYS.
MARINE...
COMBINED SEAS OF AROUND 4 FEET ARE EXPECTED THE NEXT FEW DAYS,
INCREASING BY A FEW FEET THROUGH FRIDAY, AS TRADE SWELL AND INCOMING
NORTH SWELL INCREASE. SEAS ARE EXPECTED TO REMAIN BELOW LEVELS
HAZARDOUS TO SMALL CRAFT.
FIRE WEATHER...
A TRACE OF RAIN HAS FALLEN SO FAR TODAY, NOT ENOUGH TO PUT A DENT IN
THE KBDI VALUE, WHICH HAS RISEN FURTHER TO 664 AND REMAINING IN THE
HIGH CATEGORY. THERE IS LITTLE LIKELIHOOD FOR WETTING RAINS FOR MUCH
OF THE CURRENT FORECAST PERIOD. AS SUCH, THE KBDI IS EXPECTED TO
CONTINUE TO RISE. EVEN SO, WINDS ARE EXPECTED TO REMAIN GENTLE TO
MODERATE, SO CONDITIONS CRITICAL TO FIRE WEATHER ARE NOT EXPECTED AT
LEAST OVER THE NEXT FEW DAYS.
EASTERN MICRONESIA...
A TRADE-WIND TROUGH IS PASSING THROUGH POHNPEI STATE, GENERATING
SCATTERED SHOWERS AROUND POHNPEI WITH HEAVIER SHOWERS AND ISOLATED
THUNDERSTORMS EXTENDING SOUTHWARD TO KAPINGAMARANGI. A BAND OF
CONVERGENCE IS EXTENDING ACROSS THE SOUTHERN ISLANDS OF THE MARSHALLS,
JUST SOUTH OF MAJURO, CREATING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. DRIER WEATHER IS FOUND ACROSS THE NORTHERN MARSHALL
ISLANDS, FROM MAJURO NORTHWARD. AS THE BAND OF CONVERGENCE SHIFTS
WESTWARD AND EMBEDDED TRADE-WIND TROUGHS MOVE THROUGH THE AREA OF
CONVERGENCE, EXPECTING CONVECTION TO LIFT INTO MAJURO TONIGHT. KOSRAE
IS CURRENTLY EXPERIENCING FAIRLY DRY WEATHER, BUT IT LOOKS LIKE
SHOWERS ASSOCIATED WITH THE AREA OF CONVERGENCE SOUTH OF MAJURO ARE
STARTING TO SPREAD WESTWARD, SO EXPECT SCATTERED SHOWERS TO MOVE
INTO KOSRAE LATE TONIGHT OR EARLY TOMORROW MORNING. MODEL GUIDANCE
CONTINUES TO SUPPORT A WETTER PATTERN FOR POHNPEI, KOSRAE, MAJURO AND
OTHER ISLANDS SOUTH OF 8N THROUGH THE WEEKEND INTO NEXT WEEK
SUPPORTED BY TRADE CONVERGENCE AND PASSING TRADE WIND TROUGHS.
MEANWHILE, DRIER WEATHER IS EXPECTED FOR ISLANDS NORTH OF 8N, WHICH
INCLUDES THE NORTHERN MARSHALL ISLANDS, WHERE A SUBTROPICAL RIDGE TO
THE NORTH CONTINUES TO SUPPORT SUBSIDING DRY AIR OVER AREA, AND THE
PERIODS OF DRY WEATHER IS CAUSING DROUGHT TO DEVELOP AND WORSEN.
BUOY AND ALTIMETRY DATA SHOW SEAS ARE 4 TO 5 FEET ACROSS MOST OF THE
REGION, WITH SEAS INCREASING UP TO 6 TO 7 FEET EAST OF THE MARSHALL
ISLANDS, NEAR THE DATE LINE. MODEL GUIDANCE CONTINUES TO SUPPORT
GENTLE TO MODERATE WINDS ACROSS THE REGION WITH WINDS ONLY BECOMING
SLIGHTLY STRONGER NEAR LARGE AREAS OF CONVECTION DEVELOPING WITHIN
THE AREA OF CONVERGENCE CURRENTLY SOUTH OF MAJURO. SEAS ARE EXPECTED
TO BUILD ANOTHER 1 TO 2 FEET BY THIS WEEKEND, AS THE NORTHEAST TO
EAST SWELL BUILDS SLIGHTLY AND A PULSE OF NORTH SWELL MOVES INTO THE
REGION THIS WEEKEND, DEVELOPED BY A SYSTEM WELL NORTH OF THE REGION
AND CURRENTLY MOVING TOWARDS THE ALEUTIAN ISLANDS.
WESTERN MICRONESIA...
A NEAR-EQUATORIAL TROUGH (NET) REMAINS IN THE SOUTHWEST CORNER OF THE
REGION, EXTENDING FROM AN EMBEDDED CIRCULATION NEAR 4N129E AND
CONTINUES TO EQ150E. UNSETTLED WEATHER IS FOCUSED NEAR THE
CIRCULATION, BUT OVERALL CONVECTION REMAINS UNORGANIZED FARTHER
EASTWARD. SCATTERED TO NUMEROUS SHOWERS CAN BE FOUND NEAR THE EQUATOR,
ALONG THE SOUTHERN AND EASTERN PERIPHERIES OF THE NET. NORTH OF THE
NET AND OVER THE MAIN FORECAST LOCATIONS, A SERIES OF WEAK TRADE-WIND
TROUGHS ARE EXPECTED TO PRODUCE BRIEF UPTICKS IN SHOWERS OVER THE
NEXT FEW DAYS. A BROADER TROUGH NEAR POHNPEI IS EXPECTED TO BRING
SCATTERED SHOWERS TO CHUUK ON THURSDAY. THEN, A NORTHWARD SHIFT OF
THE NET IS EXPECTED TO INCREASE CONVERGENCE ACROSS THE MAIN FORECAST
LOCATIONS LATE WEEK AND THROUGH THE MIDDLE OF NEXT WEEK, MAINLY FOR
PALAU AND CHUUK AND TO A LESSER EXTENT, YAP.
BENIGN MARINE CONDITIONS CONTINUE OVER THE NEXT SEVERAL DAYS WITH
COMBINED SEAS OF 3 TO 5 FEET EXPECTED, COMPRISED OF MINOR TRADE SWELL
AND WIND WAVES. A LONGER-PERIOD NORTH SWELL REACHES THE REGION OVER
THE WEEKEND, THIS MAY SLIGHTLY ADD TO SEAS, BUT WOULD MAINLY BOOST
SURF ALONG NORTH-FACING REEFS. NEITHER SEAS NOR SURF ARE EXPECTED TO
REACH HAZARDOUS LEVELS AT THIS TIME.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS UPDATE: DECOU
EAST/WEST MICRONESIA UPDATE: DOLL
MARIANAS: MONTVILA
EAST MICRONESIA: SCHANK
WEST MICRONESIA: CRUZ
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